Under present day conditions of world-wide shortages of energy, great emphasis is placed on the design and development of systems and devices for conserving energy in whatever form it exists. One form in particular, heat, is especially important to conserve because it is so costly to generate and so easily lost. The sharply rising costs of fuel oil in the past year of so has resulted in particular focus being directed toward systems and devices for generating heat from alternate sources of energy, and for reducing the loss of heat from residential and commercial buildings in the frigid climates.
By considering measures to reduce heat loss from buildings, an immediate concern is the problem of reduction of heat loss through windows. This problem is especially acute in residential buildings where windows are a necessity, as distinguished from commercial buildings where windows are not a necessity since, more and more in modern buildings, the environment with respect to both light and heat is entirely artificial. Various systems and materials have been devised to reduce heat loss through walls and roofs but very little has been accomplished to reduce heat loss through windows. The almost universal approach to reducing heat loss through windows is the standard double pane window panel formed of two layers of glass with a dead or stagnate trapped air space therebetween. Trapped air is a well-known and highly effective means of insulation, and is very effectively used in thermally insulating windows because the air space can be easily sealed. As a matter of fact, this is also true for doors, and many thermally insulating doors are constructed on the same principle.
While insulating windows and doors have greatly improved with respect to such characteristics as ease and convenience of storing, removing, opening, mounting or operating, as well as manufacturing techniques, frame materials and designs to reduce cost, very little, if anything has been done to improve the most significant characteristic of any thermally insulating window, i.e., its thermal insulation capability. It should be obvious to anyone that any window which can maintain an interior face temperature of 70.degree. when the exterior face temperature is 20.degree. is substantially more thermally insulating and therefore more energy efficient than a window which can maintain only a 30.degree. deferential under the same conditions.
Presently existing thermally insulating windows are not as thermally insulating as they could be for two principle reasons, firstly that they are made of glass which is itself an excellent heat conducting material, and secondly that there is only one air space between the two layers of glass so that the window will be as optically clear as possible to afford undistorted vision through the window. It is well known that the more layers of glass in the window, the more likelihood there is for optical distortions. Therefore, a compromise is sought between insulating capacity, optical clarity and costs with the result that relatively inefficient thermally insulating windows are available, at high cost.
My invention hereinafter disclosed and claimed seeks to entirely eliminate the need for the above mentioned compromise by taking full advantage of both thermal insulation and optical clarity characteristics in a multi-mode window.